Safety device for elevators



(No Model.) 2 Sheets-'Sheet 2.

I HATGH. l SAFETY DBVGB FR ELBVATORS.A

10.439,081. Patented oct. 21, 1890'.

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UNITED STATES PATENT OFFICE.

lIOHY HATCH, OF SAN FRANCISCO, CALIFORNIA.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 439,081, dated October21, 1890.

Application led March 25, 1890v Serial No. 345,197. (No model.)

To all whom, it may concern,.-

Be it known that I, JOHN HATCH, a citizen of the United States, residingin the city and county of San Francisco, State of California, haveinvented certain new and useful Improvements in Safety-Clutches forElevators, of which the following is a specification.

Certain features in thisimproved mechanism are to be found in theLetters Patent of the United States which were granted and issued to meon the 26th day of November, 1889, No. 416,000, and in several respectsthe present invention is an improvement on the devices described andcovered in that patent.

The nature of these improvements consists in placingthe friction-blocksand their operating mechanism upon a frame that is separate from thecage or platform of the elevator and is capable of independent movementto a limited extent, but always traveling with the cage. This separateframe, being counterbalanced or supported by suitable means, is adjustedto move regularly with the cage under ordinary conditions of speed; butwhen the hoisting-rope breaks or from other causes the cage is no longerunder control of the hoisting machinery, the sudden drop or movement ofthe cage operates on the friction-block levers that are mounted on theframe and brin gs the blocks into action, as hereinafter more fullydescribed.

The improvements also include certain novel construction andarrangementof double friction-blocks and toggle-levers in combination with aseparate carrying-frame on which the clutch mechanism is mounted, andalso a releasing device to throw off the frictionblocks by hand andallow the elevator to descend at slow rate of speed at any time afterthe safetydevice shall have been thrown into action.

The said improvements and the manner in which I proceed to construct andapply the same are fully explained in the following description, inwhich the accompanying drawings are referred to by letters.

Figure l represents in elevation apassengerelevator and part of theupright stationary guides with the friction-blocks and theircarrying-frame and other parts of the present improvements applied tothe elevator. Fig. 2 is A Aindicate iiXed guide-timbers eXtendi ingalong the opposite sides of the elevatorshaft, B B* B2 the parts of theelevator cage or platform, and C C C;2 the parts constituting theseparate frame on which the safety clutches or grips are mounted.

The cross-head B is a part of the elevator cage or platform, and to itis made fast the end of the hoisting-rope W. Suitable grooves in thefaces of the upright guides are provided to take the ends of thecross-head in the usual manner to steady the cage, and the sides of theguides furnish gripping-surfaces for the clutches to engage with. Thehorizontal top bars C of the separate frame eX- tend across the top ofthe cage and are connected together by the cross-bars C', while theupright bars C2, being joined to the bars C at the ends, are madesuiciently long to extend down outside of the cage and through slots c3cut for them in the platform or bottorn of the elevator. These uprightbars keep the top frame true and in level position, and also carry thelower ends of the toggle-levers that work the bottom clutches. Theweight of this frame is supported either bya rope and counter-weight T Uor by springs V V, attached to the elevator cross-head and to the topbars of the frame. In cases where the first-mentioned construction isnot applicable, as in the shaft of a mine-hoist,I suspend theclutch-frame from the elevator cross-head by springs, as illustrated inFig. 4. The rope T is attached to the loop or yoke D that is secured atthe ends CZ CZ, Fig. 3, to the top bars of the separate frame.

E E and EX EX are two sets of clutches, formed of friction-blocks havingV-shaped faces to engage the sides of the upright guides, which are ofcorresponding shape. Such form of bearing-surfaces is employed for thepurpose of increasing the amount of frictional surface; but I do notlimit the construction to that particular form of bearingiis surface, asother forms can be employed. The wedge form of sliding block andstationary rail or gripping-surface, as represented in the drawings, isprobably the best, however, for general purposes.

Gr G are horizontal levers, having points of attachment at g g to thetop frame and carrying at their outer ends the blocksE E. On the pointsgas pivots the levers have limited movement in horizontal arcs, by whichthe blocks E E are pressed against the grippingsurfaces A A, or are setclear of those surfaces, according to the directionin which the innerends of the levers are moved, whether inward or outward. The shortermembers of the levers are connected to the blocks byy hinge-joints, thatare formed of knuckles 7i 011 the back of the block, and an eye on theend of the lever, with a pivot bolt hx passing through the parts. Fromthe pivots g the levers extend toward the center of the top frame andare connected at the inner ends by links or short rods I I to thecross-head or overhead bar, to which the hoisting-rope is applied, andwhich, as before described, is a part of the elevator. The links haveeyes on both ends and are of greater length than the vertical distancebetween the levers and the overhead cross-bar, so that, being attachedto this bar under its center and to the ends of the levers, these linkswill stand outward and form a toggle-connection between the levers andthe cross-bar above them of such character that when the lever-carryingframe and the overhead cross-piece of the elevator are moved to` wardeach other the levers will be spread apart at the lower ends. By suchmovement the friction-blocks connected to the outer ends of the leverswill be pressed against the uprights A, while by a contrary movement, oras long as the separate carrying-frame and the cross-head above it arekept apart, the friction-blocks will set clear of the uprights. Underordinary conditions, when the elevator is working properly the separateframe travels regularly with the cage and preserves that position inwhich the levers hold the blocks away from the uprights, the frame beingcounterbalanced either by the rope and counter-weight applied asrepresented in Fig; l or beingsuspended at proper distance below thesprings, as illustrated in Fig. 4.

Beneath and in line with the friction-blocks E are applied blocks EX ofsimilar shape for the purpose of furnishing additionalholdin gpower.Each of these blocks is attached by a hinge-joint k' to the'corresponding block above, and each one is also connected to the angleof a toggle-lever formed of links L L and so coupled to the principallevers of the blocks E, and also attachedto the lower ends to xedpoints, that the inward movement of the outer ends of the levers bywhich the upper blocks are set operates on the toggle to bring its twomembers toward a straight line, and thereby press the blocks EX againstthe stationary upright. The links L or the upper members of the toggleare attached to the the upper block into action, and thus a muchV longerfrictional block can be used, because the pressure or force to work theblock is applied at two points in the length, both at the upper end andnear the lower end of the whole length of the frictionpiece- Inconnection with this safety device it is necessary to provide some meansfor releasing the grip of the friction-blocks on the uprights wheneverit is desired to lower the cage after the clutches have been broughtinto action and the fall of the cage has been arrested, and such a meansto be operated by hand from the inside of the cage is illustrated inFig. 4f. It is formed of a shaft P, having supports in bearings px 19Xon the upright bars c2 of the separate frame and provided with ahand-wheel pxx for turning it. To the ends of the shaft outside thebearings are attached chains R R, that have their ends fastened to theframes of the elevator at points RX R) below the line of the shaft, theconnection being such that by winding up the chains on the shaftl theseparate frame and the elevatorframe or cross-head will be drawn apart,and thereby caused to draw up the links I and move the longer members ofthe horizontal levers inward. This takes the pressure from thefriction-blocks to a greater or less degree, but should not take off thefriction altogether. The amount of such reduction in pressure againstthe uprights is regulated by turning the hand-wheel slowly until theelevator begins to move slowly of its own weight, it being understoodthat at such time the hoistingrope has become detached from the elevatorby accident or is not available to control the cage.

An important feature in this present improvement consists in providing across-head formed of two separate beams B BX, the up- IOO IIO

per one of which has the hoisting-rope at- This construction of doublevcross-head is an important addition to the above described safetymechanism vin preventing possible danger of the clutch-levers beingdetached from the cross-head of the elevator in time of accident, andthereby becoming inoperative.

Whensprings are substituted for the rope and counter-weight to suspendthe lever-carrying frame under the cross-head, the strength of thesprings to be employed is determined by the weight of the frame and mustbe of such character that the frame sets at such distance from thecross-head during the ordinary travel of the cage up and down theelevator-shaft that the blocks areheld out of frictional contact withthe stationary uprights. When the hoisting-rope breaks or no longercontrols the cage, the cross-head drops with the weight of the cage andits load independently of the traveling' frame, and the amount of suchmovement that is necessary to throw the levers being comparatively verysmall the blocks immediately act upon the stationary uprights. Thefriction thus set up acts first upon the separate frame, so that theframe and cross-head are brought closer together and the levers pressedout to their greatest extent of movement.

The traveling frame can be so regulated thata greater or less amount orvariation in the regular movement of the cage over that of the framewill throw out the levers and bring the friction-blocks against theupright guides.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is

l. In combination with an elevator cage or platform having a cross-headto which is attached the hoisting-rope, a separate traveling framecounterbalanced and suspended to travel with the cage, but to havelimited movement independent of the cage, the levers pivoted on the topof said frame, having on their outer ends friction-blocks which areadapted to engage stationary frictional surfaces against the sides ofthe elevator-shaft in the run of the cage, and their inner endsconnected by links to the cross-head of the cage, the friction-blockseach composed of two shoes connected together by a hingejoint, thetoggle-levers attached to a common point on the lower block and at thetop and bottom, respectively, to iixed points on the traveling framebelow the blocks and to the outer ends of the levers above, whereby asudden drop or downward movement of the cross-head operates on the innerends of the levers to throw their outer ends inward toward thestationary surfaces at the sides of the elevatorshaft and press thefriction-blocks against such surfaces, constructed and applied foroperation substantially as hereinbefore set forth.

2. In combination with the separatelysnspended frame adapted to travelwith and to have limited movement independently of the elevator-cage orplatform, and having levers with friction blocks or shoes on their outerends to engage stationary frictional surfaces on the sides of theelevator-shaft, and their inner ends connected to the cross-head of thecage above the frame, as described, the winding-shaf t mounted on thetraveling frame, and the chains attached to the ends of the wind,ingshaft and to the sides of the cage at points below the shaft, for thepurpose set forth.

3. In an automatic safety-clutch for elevators, the separate travelingframe composed of the bars C, C and C2, mounted on but havingindependent movement of the cage to a limited extent in a verticaldirection, in combination with the horizontal levers pivoted on the topof said frame, having their inner ends connected to the cross-head ofthe cage above by inclined links and their outer ends connected tofriction-blocks or shoes, between which the stationary guides on thesides of the elevator-shaft are arranged, as described, and the rods orbars forming toggle-levers and connected at the upper ends to the outerends of said levers and at the lower ends to fixed points blow theblocks on the side bars of t-he traveling frame, substantially as andfor the purpose set forth.

Y In testimony that I claim the foregoing I have hereunto set my handand seal.

JOHN HATCH. [L. s]

Witnesses:

EDWARD E. OsBoRN, CHAs. E. KELLY.

